To me, Endless OS seems to be the best fit for you; install it once and you never ever have to give it a second glance for troubleshooting or whatsoever. It achieves this through using "a read-only root file system managed by OSTree with apps installed using Flatpak.". This translates to:
- The most important system-related files being protected from change by yourself and others.
- Ensurance that your base installation is exactly the same as the one tested and used by its developers. And thus an (in-)direct quality control and maintenance by the very people that work on it.
- As the base system is not changing beyond what is provided by the devs, installation of applications is relegated to flatpaks (see Flathub for the App Store).
- Flatpak is a packaging format that doesn't interact with the base system to install software; think of it like how applications are installed on your phone. With this, you can still install software you need without compromising changes to the base system.